The preparation and use of 2-amino-5-halo-6-alkyl-4-pyrimidinols as antiviral agents is known (U.S. Pat. No. 3,956,302 and Nichols, Weed and Underwood, Antimicrobial Agents and Chemotherapy 9,433, 1976). Preparation of 2-amino-5-bromo-6-phenyl-4-pyrimidinol (V, where X.sub.3 is Br and X.sub.1 is phenyl) has been reported (Brown and Stevens, JCS Perkin I, 1023, 1975) but no utility has been described for this material. Snell, Elias and Freeman in GB 1,223,686 (1967) disclose a variety of 5,6-disubstituted 2-amino-4-pyrimidinols, such as 2-dimethylamino-5-bromo-6-methyl-4-pyrimidinol. Various 5-unsubstituted 2-amino-6-arylpyrimidinols are known (e.g., Shirahawa, Yakugaku Zasshi 80, 1542-50 (1960) (CA 55, 10450e); Kulkarni et al., J. Sci. & Ind. Res. India 19C, pp. 6-8 (1960) (CA 54, 22576c) and U.S. Pat. No. 2,776,283. Diuretics and cardioregulatory properties are described for various 2-amino and 2-substituted amino-5-aminomethyl and 5-aryl-6-aryl-4-pyrimidinols, U.S. Pat. No. 2,704,285, U.S. Pat. No. 2,723,977 and U.S. Pat. No. 2,776,283.